The exciting potential for deep-seated brain tumors is the ability to treat them with focused ultrasound, without damage to the intervening tissues, and without the need to open the head. MRI can provide the necessary control for these procedures through outstanding soft tissue contrast for targeting, monitoring techniques with MR thermometry, and the means to assess tissue viability immediately after treatment. The aims of this project are to improve these MR methods. Specifically, we aim to a) improve focal spot localization, b) improve temperature imaging including whole brain coverage and reduced sensitivity to artifacts, c) improved ablation in the presence of calcifications, and d) test the hypotheses that a series of ultrasound pulses do not damage brain tissue and that heat fixation occurs for temperatures greater than 60C. In addition, we will investigate the appearance of thermal lesions on DWI, MT, T1, CE, and stiffness weighted images.